1. Field of the Invention
Water-soluble polymers and copolymers, hereinafter polymeric materials, of high molecular weight have been employed to flocculate suspended solids in mining operations and in sewage and water treatment. They have also been found useful as thickeners in the paper industry and the building trade. Difficulties are encountered, however, when the polymer or copolymer is introduced to an aqueous medium. In the finely divided form, the polymeric materials tend to "skin" on the surface of the aqueous medium, more of the polymeric material being piled on the surface of the "skin" until the "skin" will no longer support the added weight, whereupon the entire mass sinks below the surface of the medium enveloped by a partially hydrated film to form an agglomeration often referred to as a "slub" or a "fish-eye". Such hydrated globules thereafter are dissolved with great difficulty, generally only after mechanical agitation over an extended period of time.
Larger particles of the polymeric material may be utilized and the "skinning" and subsequent "slub" formation is thereby avoided. While the use of larger particles avoids the "skinning" effect, it generally increases the time required for complete solution of the polymeric material as compared to the equally well-dispersed material of smaller particle size.
Good dispersion (i.e., lack of "skinning," "slubs" and "fish-eyes") has previously been attained by agitation of the aqueous medium with simultaneous addition of the polymeric material. Using this method, it is usually impossible to entirely avoid "slubs" and "fish-eyes" and though these may be mechanically filtered out or finally dissolved by extended agitation, the consequent waste of polymeric material and increase in process time is both costly and inconvenient. Additionally, extended shearing agitation fragments most polymeric materials with a loss in solution viscosity, one of the desired properties of these polymeric materials, and is to be avoided if possible.
Special equipment which utilizes the venturi effect to disperse polymeric materials in aqueous media has been devised, but care and time are needed if all "slubs" and "fish-eyes" are to be avoided.
A composition of polymeric material which is readily dispersible and rapidly soluble upon introduction into an aqueous medium is highly desirable in flocculation, coagulation, thickening and other aqueous-based processes in which such polymeric materials are employed.